This section provides background information related to the present disclosure which is not necessarily prior art.
Fabric or flexible roofs are typically incorporated into convertible vehicles to permit movement of the roof between an open state and a closed state. Recently, conventional or fixed-roof vehicles are incorporating large roof openings to provide vehicle occupants with an open-air feeling without requiring retraction of the vehicle roof, as is done in convertible vehicles. Such vehicles typically incorporate a fabric or other flexible roof panel that is selectively movable relative to a fixed roof panel between an open state and a closed state.
While vehicles with large roof openings and associated flexible roof panels provide vehicle occupants with an open-air feeling, such flexible roof panels are difficult to seal relative to the fixed roof panel. Inadequate sealing can lead to higher noise levels within a cabin of the vehicle and exposure to external temperatures or elements.
One source of such problems is separation of the flexible roof panel from the vehicle body at the fixed roof panel due to pressure differentials between the cabin interior and the vehicle exterior. For example, as vehicle speed increases, airflow around the vehicle exterior can create an area of low pressure relative to the interior cabin pressure at the flexible roof panel. This pressure differential can cause the flexible roof panel to lift up or balloon outward from the cabin, thereby causing gaps between the roof material and the vehicle body. These gaps can allow the relatively low pressure outside the vehicle to act as a vacuum to draw air from the cabin, which can cause a whistling or buffeting noise and, further, can lead to difficulty maintaining a desired cabin temperature. Such gaps further serve as pathways for external elements such as water or dirt which may enter the cabin during movement of the vehicle.
Traditional attempts to minimize separation of a flexible roof panel from a fixed roof panel include compressing large, resilient seals to such a degree that the seals expand and maintain contact with the fixed roof panel as the flexible roof panel lifts and the seals decompress. This expansion is due to the compressed geometry and material of the seal seeking to return to its decompressed state. Such seals are typically either too small to maintain contact with the roof during the full range of lift, or involve very large and/or complex geometries requiring a high degree of compressibility. In addition to seals, cables are generally included along a periphery of the flexible roof panel to maintain a predetermined tension in the material of the panel, thereby minimizing lifting. However, typical seal and cable solutions are prone to wear, are costly and complex to manufacture, and increase the weight and packaging size of the overall assembly.